scholarly journals The Genetics of Heteromeric Amino Acid Transporters

Physiology ◽  
2005 ◽  
Vol 20 (2) ◽  
pp. 112-124 ◽  
Author(s):  
Manuel Palacín ◽  
Virginia Nunes ◽  
Mariona Font-Llitjós ◽  
Maite Jiménez-Vidal ◽  
Joana Fort ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Mouse Models ◽  
Knockout Mouse ◽  
Amino Acid Transporters ◽  
Lysinuric Protein Intolerance ◽  
Lysinuric Protein ◽  
Recent Developments ◽  
Hartnup Disorder ◽  
Protein Intolerance

Heteromeric amino acid transporters (HATs) are composed of a heavy ( SLC3 family) and a light ( SLC7 family) subunit. Mutations in system b0,+ (rBAT-b0,+AT) and in system y+L (4F2hc-y+LAT1) cause the primary inherited aminoacidurias (PIAs) cystinuria and lysinuric protein intolerance, respectively. Recent developments [including the identification of the first Hartnup disorder gene (B0AT1; SLC6A19)] and knockout mouse models have begun to reveal the basis of renal and intestinal reabsorption of amino acids in mammals.

Apical Transporters for Neutral Amino Acids: Physiology and Pathophysiology

Physiology ◽  
2008 ◽  
Vol 23 (2) ◽  
pp. 95-103 ◽  
Author(s):  
Stefan Bröer
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Molecular Identification ◽  
Molecular Basis ◽  
Amino Acid Transporters ◽  
Lysinuric Protein Intolerance ◽  
Inherited Disorders ◽  
Lysinuric Protein ◽  
Hartnup Disorder ◽  
Protein Intolerance

Absorption of amino acids in kidney and intestine involves a variety of transporters for different groups of amino acids. This is illustrated by inherited disorders of amino acid absorption, such as Hartnup disorder, cystinuria, iminoglycinuria, dicarboxylic aminoaciduria, and lysinuric protein intolerance, affecting separate groups of amino acids. Recent advances in the molecular identification of apical neutral amino acid transporters has shed a light on the molecular basis of Hartnup disorder and iminoglycinuria.

scholarly journals A global Slc7a7 knockout mouse model demonstrates characteristic phenotypes of human lysinuric protein intolerance

2020 ◽  
Vol 29 (13) ◽  
pp. 2171-2184
Author(s):  
Bridget M Stroup ◽  
Ronit Marom ◽  
Xiaohui Li ◽  
Chih-Wei Hsu ◽  
Cheng-Yen Chang ◽  
...  
Keyword(s):  
Mouse Model ◽  
Knockout Mouse ◽  
Skeletal Development ◽  
Growth Failure ◽  
Tubular Dysfunction ◽  
Micro Computed Tomography ◽  
Lysinuric Protein Intolerance ◽  
Knockout Mouse Model ◽  
Lysinuric Protein ◽  
Protein Intolerance

Abstract Lysinuric protein intolerance (LPI) is an inborn error of cationic amino acid (arginine, lysine, ornithine) transport caused by biallelic pathogenic variants in SLC7A7, which encodes the light subunit of the y+LAT1 transporter. Treatments for the complications of LPI, including growth failure, renal disease, pulmonary alveolar proteinosis, autoimmune disorders and osteoporosis, are limited. Given the early lethality of the only published global Slc7a7 knockout mouse model, a viable animal model to investigate global SLC7A7 deficiency is needed. Hence, we generated two mouse models with global Slc7a7 deficiency (Slc7a7em1Lbu/em1Lbu; Slc7a7Lbu/Lbu and Slc7a7em1(IMPC)Bay/em1(IMPC)Bay; Slc7a7Bay/Bay) using CRISPR/Cas9 technology by introducing a deletion of exons 3 and 4. Perinatal lethality was observed in Slc7a7Lbu/Lbu and Slc7a7Bay/Bay mice on the C57BL/6 and C57BL/6NJ inbred genetic backgrounds, respectively. We noted improved survival of Slc7a7Lbu/Lbu mice on the 129 Sv/Ev × C57BL/6 F2 background, but postnatal growth failure occurred. Consistent with human LPI, these Slc7a7Lbu/Lbu mice exhibited reduced plasma and increased urinary concentrations of the cationic amino acids. Histopathological assessment revealed loss of brush border and lipid vacuolation in the renal cortex of Slc7a7Lbu/Lbu mice, which combined with aminoaciduria suggests proximal tubular dysfunction. Micro-computed tomography of L4 vertebrae and skeletal radiographs showed delayed skeletal development and suggested decreased mineralization in Slc7a7Lbu/Lbu mice, respectively. In addition to delayed skeletal development and delayed development in the kidneys, the lungs and liver were observed based on histopathological assessment. Overall, our Slc7a7Lbu/Lbu mouse model on the F2 mixed background recapitulates multiple human LPI phenotypes and may be useful for future studies of LPI pathology.

scholarly journals Inducible Slc7a7 Knockout Mouse Model Recapitulates Lysinuric Protein Intolerance Disease

2019 ◽  
Vol 20 (21) ◽  
pp. 5294 ◽  
Author(s):  
Bodoy ◽  
Sotillo ◽  
Espino-Guarch ◽  
Sperandeo ◽  
Ormazabal ◽  
...  
Keyword(s):  
Knockout Mouse ◽  
Failure To Thrive ◽  
Neurological Impairment ◽  
Lysinuric Protein Intolerance ◽  
Metabolic Derangement ◽  
Knockout Mouse Model ◽  
Cationic Amino Acid ◽  
Promising Tool ◽  
Lysinuric Protein ◽  
Protein Intolerance

Lysinuric protein intolerance (LPI) is a rare autosomal disease caused by defective cationic amino acid (CAA) transport due to mutations in SLC7A7, which encodes for the y+LAT1 transporter. LPI patients suffer from a wide variety of symptoms, which range from failure to thrive, hyperammonemia, and nephropathy to pulmonar alveolar proteinosis (PAP), a potentially life-threatening complication. Hyperammonemia is currently prevented by citrulline supplementation. However, the full impact of this treatment is not completely understood. In contrast, there is no defined therapy for the multiple reported complications of LPI, including PAP, for which bronchoalveolar lavages do not prevent progression of the disease. The lack of a viable LPI model prompted us to generate a tamoxifen-inducible Slc7a7 knockout mouse (Slc7a7−/−). The Slc7a7−/− model resembles the human LPI phenotype, including malabsorption and impaired reabsorption of CAA, hypoargininemia and hyperammonemia. Interestingly, the Slc7a7−/− mice also develops PAP and neurological impairment. We observed that citrulline treatment improves the metabolic derangement and survival. On the basis of our findings, the Slc7a7−/− model emerges as a promising tool to further study the complexity of LPI, including its immune-like complications, and to design evidence-based therapies to halt its progression.

scholarly journals Waste Nitrogen Excretion Via Amino Acid Acylation: Benzoate and Phenylacetate in Lysinuric Protein Intolerance

1986 ◽  
Vol 20 (11) ◽  
pp. 1117-1121 ◽  
Author(s):  
Olli Simell ◽  
Ilkka Sipilä ◽  
Jukka Rajantie ◽  
David L Valle ◽  
Saul W Brusilow
Keyword(s):  
Amino Acid ◽  
Nitrogen Excretion ◽  
Lysinuric Protein Intolerance ◽  
Lysinuric Protein ◽  
Protein Intolerance
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